The Apache License is a free and open source software license written by the Apache Software Foundation (ASF) that is currently in its third iteration. It allows software and projects to be freely used, modified, or redistributed under the terms of the license for personal, commercial, or company purposes without concern for royalties. Apache encourages users to voluntarily improve the design of software applications through open source code.
ASF and its projects release their software products under the Apache License, but the license is also used by many non-ASF projects. The Apache web server was the first project to be licensed under the Apache license.
Apache License terms and conditions
The Apache license is a permissive license, meaning it doesn’t require a derivative work of the software or modifications done to the software to be distributed using the same license.
The license permits rights to users for both copyright and patents, whereas other permissive licenses only grant rights for copyrights. The rights are unending, global, irreversible, and also non-exclusive, meaning anyone can use the license. If a user wishes to redistribute software with an Apache License component, a copy of the license, attribution, and notices to all modified files must be included.
Modified or derived products can be released under different licenses, however the unmodified parts must retain the Apache License. In addition, modified versions cannot be given a name that suggests endorsement or creation by the ASF. Copyright statements can be added to modifications done to any Apache-licensed software, and terms and conditions can be added to control how others use, reproduce, or distribute the modified code.
Versions of the Apache License
The first Apache license was released in 1995 by the Apache Group (now known as ASF), but this version is rarely used. The Apache License 1.1 was released in 2000 and had removed the advertising clause, meaning advertising materials of the derivative works of any Apache-licensed product no longer required including the Apache License attribution. The most recent version, Apache License version 2.0 was released in 2004 and was created to make use easier for non-ASF projects, improve compatibility with GPL-based software, and grant patent rights.